Infrared ThermometerInfrared Thermometer

Luke M. SnellLuke M. Snell

Concrete Industry ManagementConcrete Industry ManagementDel E. Webb School of ConstructionDel E. Webb School of Construction

Arizona State UniversityArizona State UniversityTempe ArizonaTempe Arizona

Traditional Approx of TemperatureTraditional Approx of Temperature

Steel Temperature: Steel Temperature:

. Dull Red Color- 550 C . Dull Red Color- 550 C

. Yellow Hot Color- 1150 C . Yellow Hot Color- 1150 C

. White Hot Color- 1500 C . White Hot Color- 1500 C

Emissivity Theory Used for Infrared Emissivity Theory Used for Infrared ThermometerThermometer

Infra-red

How IR Thermometer WorksHow IR Thermometer Works

Emitted Energy indicates the Emitted Energy indicates the temperature of the object.temperature of the object.

When IR thermometer senses the When IR thermometer senses the energy and converts to temperatureenergy and converts to temperature

Product DescriptionProduct Description Temperature range : -18 to 275 CTemperature range : -18 to 275 C

Accuracy: ± 2%, or ± 2°C whichever is greater Accuracy: ± 2%, or ± 2°C whichever is greater

Response time: 500mSecResponse time: 500mSec

Ambient operating range: 0 to 50 C Ambient operating range: 0 to 50 C

Power: 9V alkaline or NiCd Battery includedPower: 9V alkaline or NiCd Battery included

Temperature display: C or F , selectableTemperature display: C or F , selectable

LimitationsLimitations

Measures only surface temperature ,not Measures only surface temperature ,not the internal temperaturethe internal temperature

Can not shoot through windowsCan not shoot through windows

Laser Warning- need to be careful Laser Warning- need to be careful

Obstruction – smoke and dust particlesObstruction – smoke and dust particles

Application in Concrete ConstructionApplication in Concrete Construction

IR thermometer can:IR thermometer can:

Measure forms and reinforcement Measure forms and reinforcement temperatures prior to placement (Less temperatures prior to placement (Less than 50 C)than 50 C)

Estimate concrete temperatures during Estimate concrete temperatures during placement (4 to 30 C).placement (4 to 30 C).

Application in Concrete ConstructionApplication in Concrete Construction

IR Thermometer can:IR Thermometer can: Measure temperature of soil/base ( must Measure temperature of soil/base ( must

be above freezing)be above freezing)

Monitor curing environment for first 7 Monitor curing environment for first 7 days (should be maintained above 4C)days (should be maintained above 4C)

Temperature controlTemperature control

-7

7

12

25

4240

3433

21

17

14

-20

-10

0

10

20

30

40

50

0 1 2 6 10 14 18 22 42 46.5 47.5

Temperature (C)

Curing temperatures graph (C)

Disconnected time

Time (hour)

T= T= 0.22 (TaMa + TcMc) + TwMw0.22 (TaMa + TcMc) + TwMw

0.22 (Ma + Mc) = Mw0.22 (Ma + Mc) = Mw

T = temperature of concrete, CT = temperature of concrete, C

Ta,Tc,Tw = temperature of aggregate,Ta,Tc,Tw = temperature of aggregate,

cement, water, Ccement, water, C

Ma,Mc,Mw = Mass (weight) of material Ma,Mc,Mw = Mass (weight) of material in mixture, kg in mixture, kg

EXAMPLE:EXAMPLE:

Mixture, kg per cubic meterMixture, kg per cubic meter

Aggregates, 1839 kg @ 27CAggregates, 1839 kg @ 27C

Cement, 335 kg @ 66 CCement, 335 kg @ 66 C

Water, 123 kg @ 27C Water, 123 kg @ 27C

Temperature of Concrete = 31.8CTemperature of Concrete = 31.8C

Need to chill water to 17C if concrete Need to chill water to 17C if concrete temperature is required to be less than temperature is required to be less than 30C30C

Using IR in MongoliaUsing IR in Mongolia

Water heated to 56 CWater heated to 56 C Fine aggregates - 18 CFine aggregates - 18 C Coarse aggregates - 19 CCoarse aggregates - 19 C Bags of cement - 19 CBags of cement - 19 C

Calculated temperature 4 CCalculated temperature 4 C IR temperature 1CIR temperature 1C

Where do you measure temperature Where do you measure temperature with IR?with IR?

Research project – measure concrete atResearch project – measure concrete at::

Forms, wheel barrows or buggiesForms, wheel barrows or buggies

Revolving drumRevolving drum

ChuteChute

Chutes provide accurate temperaturesChutes provide accurate temperatures

ConclusionConclusion IR thermometer can be used by the IR thermometer can be used by the

contractor to monitor the temperature of contractor to monitor the temperature of the concrete. the concrete.

IR thermometers to determine if IR thermometers to determine if adequate curing of the concrete is adequate curing of the concrete is achieved in hot /cold weather achieved in hot /cold weather construction.construction.